Domain and range of functions Example: f(x)=x+1, if x<0 f(x)=x+2, if x>=1 The domain of f is: "x<0 or x>=1" The range of f is: "y<1 or y>=2" What is the simplest way to draw the domain (on x-axis) and range (on y-axis)? Command if(-inf<f(x)<inf,0) seems to work always, on all functions (domain on x-axis). But command (for range on y-axis), f(t)*(0,1) At first it seems to work fine (after changing the values of t, if necessary). But later it will create error messages on some situations. After these erros, command a:X=f(t)*(0,1) was successful. This is very strange! (By the way, here is again a letter, now X, with a special property - it cannot be replaced - it is like x, y, z and t!) Here is my main problem: Reliable and easy way to draw the set: A = { (0,y) | y=f(x) for some x }